Our long-term goal is to develop non-toxic, low-cost and efficacious herbal modalities from Korean Angelica gigas Nakai (AGN) for the prevention of prostate carcinogenesis and metastasis in men. We have shown in preclinical models significant prostate cancer growth-inhibitory and chemopreventive effects of AGN ethanol extracts without any observable toxicity to the host mice. Nevertheless, a lack of mechanistic knowledge of active chemicals and in vivo molecular targets is a significant roadblock to translating the preventive benefits to men. The objective for the current application is to generate mechanistic knowledge of (1) the active chemicals and (2) cellular and molecular targets in two independent and complementary prostate cancer models. We hypothesize that AGN extract exerts in vivo efficacy (a) mainly through pyranocoumarin compounds and their metabolite; (b) by affecting critical cellular processes and molecular targets, which can be effectively profiled through a systems-biology approach. We plan to test these hypotheses by pursuing three specific aims: Aim 1. Establish the chemical mediator role of the pyranocoumarins by comparing the efficacy of purified compounds with AGN extract and pyranocoumarin-knockout (KO) extract to inhibit human prostate cancer growth and metastasis in xenograft models in immunodeficient mice. Aim 2. Validate their mediator role for chemopreventive efficacy against primary carcinogenesis in the transgenic adenocarcinoma of mouse prostate (TRAMP) model by comparing them with AGN extract and KO extract. Aim 3. Determine key cellular indices and molecular biomarkers of in vivo efficacy including angiogenesis, apoptosis, cell proliferation and invasiveness by focused analyses and identify molecular targets with systems-biology approaches, using suitable tissues from the first two aims. The work proposed in Aims 1 and 2 is expected to critically assess the role of pyranocoumarins and metabolites as chemical mediators for the inhibitory efficacy of AGN extract against prostate primary carcinogenesis and metastasis, and establish their long-term safety profiles in mice models. Such results are expected to positively impact future focused R&D efforts and quality control for AGN herbal products. Aim 3 results are expected to identify candidate in vivo molecular targets and cellular processes. Better knowledge of the active chemicals and their molecular targets in model systems enables further mechanistic studies and rational planning for clinical translation in men. Furthermore, the efficacy and mechanisms are likely exportable to the prevention of cancers of other organ sites by AGN extracts. The research proposed is innovative, in our opinion, because it represents a substantial departure from the status quo for preclinical cancer chemoprevention research of single-agent/single-target approach. The comprehensive research with cutting- edge medicinal chemistry methods (e.g., knockout extract) and systems-biology tools (e.g., iTRAQ proteomics) can help moving herbal remedies toward evidence-based complementary and alternative medicine.